Additions to CC

Metal complexes as catalysts for oxygen, nitrogen and carbon-atom transfer reactions (Tsutomu Katsuki) Metal complexes as catalysts for H-X (X = B,CN, Si, N, P) addition to CC multiple bonds (M. Whittlesey) Metal complexes as catalysts for C-C cross-coupling reactions (I. Beletskaya, A.V. Cheprakov)... 

Although these additions to CO double bonds have some superficial similarities to the electrophilic additions to CC double bonds that were presented in Chapter 11, there are many differences. The acidic conditions mechanism here resembles the mechanism for addition to carbon-carbon double bonds in that the electrophile (the proton) adds first, followed by addition of the nucleophile. However, in this case the first step is fast because it is a proton transfer involving oxygen, a simple acid-base reaction. The second step, the attack of the nucleophile, is the rate-determining step. (Recall that it is the first step, the addition of the electrophile, that is slow in the additions to CC double bonds.) Furthermore, in the case of additions to simple alkenes there is no mechanism comparable to the one that operates here under basic conditions, in which the nucleophile adds first. Because the nucleophile adds in the slow step, the reactions presented in this chapter are termed nucleophilic additions, even if the protonation occurs first. In... 

Addition to CC multiple bonds. Allenes are carboxylated at the central carbon by the Ni-catalyzed reaction with CO2, hydroxylation follows on subsequent exposure to oxygen7... 

Fig. 2.3 P/C rings (4, 6, 1) obtained from phosphinidene addition to CC triple bonds...

A MIXTURE of 120 g. (3 moles) of sodamide (Note i) and 200 cc. of purified mineral oil (Note 2) is ground together in a mortar until the amide is finely pulverized (Note 3). This suspension is transferred to a 2-I. round-bottom, three-necked flask fitted with a reflux condenser holding a calcium chloride tube, a 500-cc. separatory funnel, and an efficient mechanical stirrer through a mercury seal. The mortar and pestle are rinsed with an additional 250 cc. of the oil which is then added to the reaction flask. This is heated in an oil bath maintained at 160-165, the stirrer is started and 203 g. (i mole) of cyclohexylbromopropene (p. 20) is dropped in during one and one-half hours. Ammonia is evolved and this is allowed to pass through the condenser and is collected in water. 

A mixture of 7.8 grams (0.05 mol) of )3-(p-aminophenyl)ethyl chloride hydrochloride, 12.5 grams (0.025 mol) of 4-phenyl-4-carboethoxypiperidine carbonate, 10.5 grams (0.125 mol) sodium bicarbonate, and 100 cc of anhydrous ethanol are mixed, stirred and heated under reflux for a period of approximately 40 hours and then concentrated in vacuo to dryness. The residual material is triturated with 50 cc of water, decanted, washed by decantation with an additional 50 cc of water, and then dried in vacuo to give N-[)3-(p-aminophenyl)-ethyl] -4-phenyl-4-carboethoxypiperidine. 

Reduction of 16-keto-17(0i)-hydroxyestratrienol-3-methyl to 16,17-dihydroxyestratrienol-3-methyl ether A solution of 800 mg of the alpha ketol methyl ether in 100 cc of ethanol and 10 cc of acetic acid was carefully maintained at 40°C (water bath), and 200 g of freshly prepared sodium amalgam (2%) were added in small pieces with efficient swirling. Before all of the amalgam had been added, a precipitation of sodium acetate occurred, and at this point an additional 100 cc of 50% acetic acid were added. After all the reducing agent had been added, the mixture was transferred to a separatory funnel with ether and water. 

A solution of 2 grams of A -19-norandrosten-3,17-dione and 0.4 gram of pyridine hydrochloride in 50 cc of benzene free of thiophene was made free of moisture by distilling a small portion 4 cc of absolute alcohol and 4 cc of ethyl orthoformate were added and the mixture was refluxed during 3 hours. 5 cc of the mixture were then distilled and after adding an additional 4 cc of ethyl orthoformate the refluxing was continued for 2 hours longer. The mixture was evaporated to dryness under vacuum and the residue was taken up in ether, washed, dried and evaporated to dryness. The residue was crystallized from... 

On evaporating the alcoholic solution under reduced pressure from a water bath held at 50-60° (Note 6) the residue weighs about 540 g. A mixture of 600 cc. of absolute alcohol and 10 cc. of concentrated sulfuric acid (Note 7) is then added. The mixture is then heated on the water bath under a reflux condenser for three hours. The excess of alcohol and some of the water formed are removed by distillation under reduced pressure and the residue again heated for two hours with 300 cc. of absolute alcohol and an additional 4 cc. of concentrated sulfuric acid. The alcohol is removed by distillation under reduced pressure, and when the ester has cooled to room temperature, the sulfuric acid is neutralized with a concentrated solution of sodium carbonate the ester (upper layer) is separated, and the aqueous solution extracted with ether, or preferably benzene about one-tenth of the yield is in the extract. The combined products are placed in a i-l. distilling flask and distilled under reduced pressure after the solvent and alcohol and water have been removed. The ester is collected at 94-990, chiefly at 97-98°/x6 mm. (Note 8). The yield of a product analyzing about 97-98 per cent ethyl cyanoacetate amounts to 474-492 g. (77-80 per cent of the theoretical amount) (Note 9). 

Conjugate Addition. To a solution of 1.5 mmol of lithium dialkylcuprate at — 25 CC is added 1 mmol of methyl ( )-3-[(25,45,55)-3-benzyloxycarbonyl-4-methyl-5-phenyl-2-oxazolidinyl]-propenoate dissolved in 1 mL of dry diethyl ether. After 30 ntin at — 25 C, the mixture is treated with an aq NH3/NH4C1 pH 8 buffer solution and then stirred at r.t. for 15 min. After diethyl ether extraction, the organic layers are dried over Na,S()4 and filtered and the solvent is evaporated under reduced pressure. The crude products are checked by H- and l3C-NMR analyses in order to determine the diastereomer ratios (g 95 5) and then purified by flash chromatography (hexane/ethyl acetate 80 20) yield 70-72%. 

The conjugate addition to acyclic enones is summarized in Table 5. The chiral hetero-cuprate derived from (S)-prolinol or cinchonidine produced products of low enantiomeric excess on treatment with chalcone (entries 3 and 4), while the cuprate from (S)-yV-methylpro-linol gave 64% ee (entry 6). Under more dilute conditions, 88% cc was obtained (entry 5). (2[Pg.909]

The TGA system was a Perkin-Elmer TGS-2 thermobalance with System 4 controller. Sample mass was 2 to 4 mgs with a N2 flow of 30 cc/min. Samples were initially held at 110°C for 10 minutes to remove moisture and residual air, then heated at a rate of 150°C/min to the desired temperature set by the controller. TGA data from the initial four minutes once the target pyrolysis temperature was reached was not used to calculate rate constants in order to avoid temperature lag complications. Reaction temperature remained steady and was within 2°C of the desired temperature. The actual observed pyrolysis temperature was used to calculate activation parameters. The dimensionless "weight/mass" Me was calculated using Equation 1. Instead of calculating Mr by extrapolation of the isothermal plot to infinity, Mr was determined by heating each sample/additive to 550°C under N2. This method was used because cellulose TGA rates have been shown to follow Arrhenius plots (4,8,10-12,15,16,19,23,26,31). Thus, Mr at infinity should be the same regardless of the isothermal pyrolysis temperature. A few duplicate runs were made to insure that the results were reproducible and not affected by sample size and/or mass. The Me values were calculated at 4-minute intervals to give 14 data points per run. These values were then used to... 

By contrast, L-phenylalanine methyl ester does not react with BENA generated from 1-nitropropane (R =H) due apparently to low nucleophilicity of the amino group. However, the N, C -coupling reaction of the ester of this amino acid with another internal BENA (R = CC>2Me) proceeds rather readily but is characterized by extremely low diastereoselectivity. Probably, the last N,C-coupling does not occur via an intermediate a-nitroso alkene but by a classical Michael addition to BENA MeCH=C(C02Me)N(05i )2 as to Michael substrate. 

Pore size distribution data obtained from adsorption isotherms and from mercury porosimetric measurements show that in addition to the micropores characteristic of the parent zeolite, the DAY zeolites contain secondary pores with radii of 1.5nm (supermicropores) and lOnm (mesopores) (36,47). The secondary pores in USY-B have a radius of 5nm. It was also shown that the micropore volume of DAY amounts to about 75 percent of that of NaY (36). Due to dealumination and the formation of secondary pores, the total pore volume of DAY is considerably larger than that of NaY zeolite (0.56 vs. 0.29 cc/g). 

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